Increase In Power Density Research Articles

First results from third harmonic ion cyclotron acceleration of deuterium beams in EAST ion heating studies experiments

Recent Experimental Advanced Superconductivity Tokamak experiments have been dedicated to the studies of increasing ion temperature using Neutral Beam Injection (NBI) in synergy with radio-frequency waves in the Ion Cyclotron Range of Frequencies (ICRFs) in third harmonic. They showed that this scenario effectively accelerates fast deuterium ions and produces a larger tail of fast neutrons with E > 3.0 MeV, as measured by Neutron Energy Spectrum. Comparing to the scenario with 2.2 MW NBI alone, adding an addition of 0.3 MW ICRF power leads to an enhancement of fusion yield by 67% (from to ) and an increase of core ion temperature by . Besides, the simulation results of TRANSP show that the neutron yield produced by 0.2 MW ICRF in third harmonic with NBI synergy is roughly consistent with the experimental results. Meanwhile, the 80 keV fast ion tail generated by NBI can be heated up to 400 keV and 600 keV by the 0.2 MW and 1.0 MW ICRF with the synergistic effect, respectively. In addition, it is observed for the first time that this ICRF-NBI synergy leads to the excitation of fishbone instabilities with characteristic frequencies of (10–20) kHz. Furthermore, parameter scans of ICRF/NBI power and plasma density were performed for third harmonic ICRF and NBI synergetic heating schemes. It is found that the neutron yield increases nonlinearly as the ICRF power or plasma density increases.

Metal Additive Microfabrication of System-in-Package with Embedded Microfluidic Thermal Management for Heterogeneous Integration with Semiconductor Dies

The scaling of components on a single semiconductor chip has enabled the doubling of performance every 2 years as per Moore’s law, and has been possible due to the miniaturization of individual components. A significant decrease in transistor gate length and increase in component density has also introduced an increase in power density. Hence, there is a dire need for embedded thermal management of these systems-on-chips (SoCs) to remove waste heat. In this work, the metal additive microfabrication of a system-in-package (SiP) package with multiple pads for quad flat no-lead (QFN) packaging and a microfluidic channel and pin fin heat sinks for thermal management are presented. This work introduces heterogeneous integration (integration of separately manufactured components into a SiP for improved functionality) of SiPs fabricated using additive microfabrication to clean-room-fabricated integrated circuits (ICs) for improved functionality in terms of the thermal management of high-power density SoCs. The packages have been fabricated via a metal additive manufacturing technique, direct metal laser sintering (DMLS), using 316L stainless steel as the precursor powder. The work also opens doors to the fabrication and integration of metal microsystems using DMLS to complement semiconductor manufacturing and packaging processes. The use of air or water as the coolant for the packaging devices decreased the thermal resistance from 5.25°C/W for the conventional packages to 2.02°C/W for a flow rate of 84 mL/min when subjected to a constant heat flux. The average surface temperature also decreased from 45.61°C to 29.23°C for the same parameter. This article details the material characteristics and thermal performance of the metal additively microfabricated SiPs.

Drop impact phenomena and spray cooling on hot nanotextured surfaces of various architectures and dynamic wettability

Spray cooling has been used to quench metal slabs during casting, cool nuclear reactors, suppress accidental fires, and remove heat from high-power density electronics. In particular, the miniaturization of electronic devices inevitably results in an increased power density or heat flux on the microelectronics surfaces and poses a threat of a thermal shutdown of such devices when cooling is insufficient. Surface nanotexturing effectively augments additional liquid-to-substrate surface area, thereby increasing cooling capability, as well as an effective heat transfer coefficient. In spray cooling, surface dynamic wettability also affects drop impact dynamics and subsequent coolant evaporation on a hot surface. Herein, we introduced various nanotextured surfaces and affected dynamic wettability using the so-called thorny-devil nanofibers, nickel nanocones, Teflon and titania nanoparticles, and zinc nanowires. The effect of these different nanoscale architectures on drop impact phenomena and subsequent evaporative cooling was investigated. These nanotextured surfaces were fabricated using various deposition methods, including electrospinning, electroplating, supersonic spraying, aerosol deposition, and chemical bath deposition. We found that the surface with greater dynamic wettability related to the hydrodynamic focusing considerably improved the heat removal capability by furthering the Leidenfrost limit and facilitating drop spreading. In particular, the thorny-devil nanofiber surface yielded the highest heat flux at all ranges of the Reynolds and Weber numbers. Spray cooling on a model electronic kit also confirmed that the thorny-devil nanofibers were most effective in cooling the surface of the model kit during multiple cycles of water spraying.

Sulfonated Polybenzimidazole as a PEM in a Microbial Fuel Cell: An Efficient Strategy for Green Energy Generation and Wastewater Cleaning

A microbial fuel cell (MFC) is a bioelectrochemical system that has a dual application: producing renewable energy and simultaneously purifying dirty water. However, low power density and high installation cost are the major limitations. To overcome these problems and to replace the highly expensive Nafion which is used as a proton exchange membrane (PEM) in MFCs, here, in this study, a high-molecular weight sulfonated oxybispolybenzimidazole (MSOPBI) membrane has been made from the newly synthesized sulfonated diacid monomer in a readily executable synthetic path and cost-effective manner, and finally, the MSOPBI membrane has been tested in a dual-chamber MFC. The newly synthesized MSOPBI membrane displayed less water uptake, moderate ion exchange capacity (IEC) and proton conductivity in the hydrated state, low dimensional swelling, and phase-separated morphology with enhanced mechanical strength due to the more compact and rigid structure of the membrane owing to the crosslinking between the sulfonic functional group and imidazole group. It demonstrated a higher MFC performance because of the various favorable factors including morphological features. The MFC operation in the presence of the MSOPBI membrane when compared with that with Nafion showed an open-circuit voltage (OCV) of 345 mV, a power density of 280 mW/m2, and a current density of 2.2 mA/m2 from the polarization curves with a relatively less voltage drop. Compared to Nafion, MSOPBI showed an increase in power density by 47%. Electrochemical analysis (OCV, cyclic voltammetry (CV), linear sweep voltammetry (LSV), Tafel curves) depicted the increased bioelectrochemical activity during the MFC operation in the presence of MSOPBI owing to its compositional and low-swelling characteristic functionality that impacted the decreased resistances and system losses toward enhanced power/energy output compared to that with the Nafion membrane. All these data together proved the effectiveness of the newly synthesized MSOPBI membrane for use in MFCs for the production of green energy and cleaning wastewater.

A neutral pH aqueous biphasic system applied to both static and flow membrane-free battery

Here, we present a new aqueous biphasic system (ABS) with near neutral pH and containing highly soluble organic/organometallic active species that avoids crossover due to the thermodynamic separation of active species. This ABS become the best example of “Static” Membrane-Free Battery with the highest maximum theoretical energy density (21.7 Wh L−1), enhanced coulombic efficiency (96%) and stable performance over 250 cycles. Moreover, this work assesses the process of the self-discharge stablishing for the first time a protocol to quantify this phenomenon that results in low coulombic efficiencies in membrane-free batteries. Remarkably, a radically new membrane-free flow-reactor was specifically designed to maintain a stable liquid-liquid interphase that allows the battery to operate under flowing conditions. This resulted in flow battery with a two-fold increase of power density, high coulombic efficiencies and excellent capacity retention over 100 cycles. This work demonstrates for the first time the feasibility of this biphasic electrolyte concept in a truly Membrane-free “Flow” Battery.

Dual-Mode Coupled Triboelectric Nanogenerator for Harvesting Random Vibration Energy.

As a new energy harvesting technology, triboelectric nanogenerators are widely used for vibration mechanical energy harvesting. However, the current schemes ignore the composite characteristics of vibration, with problems such as utilization and low collection efficiency. In this paper, a random resonance cantilever beam triboelectric nanogenerator (RCB-TENG) with dual-mode coupled is presented, the working mode is a coupling form of in-plane sliding and vertical contact-separation that can effectively collect complex vibration energy in transverse and longitudinal directions. The influences of the structural parameters of the RCB-TENG and different dielectric materials on the output performance are systematically investigated. The single vibration module achieved a power density of 463.56 mW/m2 and a transfer charge of 10.7 μC at a vibration frequency of 46 Hz, an increase in power density, and a transfer charge of 4.94 and 3.82 times, respectively, compared to the conventional contact-separation mode. Finally, the RCB-TENG was tested in practice, and it was observed that nine 1 W commercial LED bulbs and 500 5 mm diameter LED lamps were successfully lit. This work offers new ideas for distributed energy harvesting technologies and holds broad promise in the field of energy harvesting from wind, water, wave, and random vibrations caused by mechanical energy.

High-consistency proton exchange membrane fuel cells enabled by oxygen-electron mixed-pathway electrodes via digitalization design

Proton exchange membrane (PEM) fuel cell has been regarded as a promising approach to the decarbonization and diversification of energy sources. In recent years, durability and cost issues of PEM fuel cells are increasingly significant with the rapid increase of power density. However, the failure to maintain the cell consistency, as one major cause of the above issue, has attracted little attention. Therefore, this study intends to figure out the underlying cause of cell inconsistency and provide solutions to it from the perspective of multi-physics transport coupled with electrochemical reactions. The PEM fuel cells with electrodes under two compression modes are firstly discussed to fully explain the relationship of cell performance and consistency to electrode structure and multi-physics transport. The result indicates that one main cause of cell inconsistency is the intrinsic conflict between the separated transport and cooperated consumption of oxygen and electron throughout the active area. Then, a mixed-pathway electrode design is proposed to reduce the cell inconsistency by enhancing the mixed transport of oxygen and electron in the electrode. It is found that the mixing of pathways in electrodes at under-rib region is more effective than that at the under-channel region, and can achieve an up to 40% reduction of the cell inconsistency with little (3.3%) sacrificed performance. In addition, all the investigations are implemented based on a self-developed digitalization platform that reconstructs the complex physical–chemical system of PEM fuel cells. The fully observable physical information of the digitalized cells provides strong support to the related analysis.

Towards commercialization of fluorinated cation-disordered rock-salt Li-ion cathodes.

Cation-disordered rock-salt cathodes (DRX) are promising materials that could deliver high capacities (>250mAh g-1) with Earth abundant elements and materials. However, their electrochemical performances, other than the capacity, should be improved to be competitive cathodes, and many strategies have been introduced to enhance DRXs. Fluorination has been shown to inhibit oxygen loss and increase power density. Nevertheless, fluorinated cation-disordered rock-salts still suffer from rapid material deterioration and low scalability which limit their practical applications. This mini-review highlights the key challenges for the commercialization of fluorinated cation-disordered rock-salts, discusses the underlying reasons behind material failure and proposes future development directions.

Effect of aluminum-based additives on the ignition performance of ammonium perchlorate-based composite solid propellants

The addition of aluminum particles in composite propellants has a positive effect on the performance of solid rocket motor, while it also brings some changes in the ignition behaviors. To clarify the ignition process and performance of aluminized propellants, a visualization experimental system was built. It is found that the ignition process of aluminized propellants mainly includes heating and melting of the solid phase, evaporation, mixing and ignition of decomposed gas. Besides, few aluminum particles agglomerate together and they are not ignited during the ignition process of propellants. According to the process of ignition, the ignition delay time can be described as the sum of pyrolysis time, mixing time and chemical reaction time. After the propellants is ignited and the stable flame is formed, the aluminum particles on the burning surface mainly undergo exposure – accumulation – fusion – separation – ignition – combustion. And the structure of the agglomerate transitions from a coral-like to an oxidized cap. At the same time, the ignition of agglomerated products occurs in the stable flame. With the increase of aluminum content and initial aluminum particle size, the ignition delay time also increases, but the proportion of these three times in the ignition delay is not very much related to the formulation of propellants. With the increase of power density of ignition, the ignition delay time decreased markedly, but the decreasing trends continuously became more gradual and eventually flattened out. As the power density of ignition increases, the percentage of pyrolysis time in the ignition delay time decreases rapidly and gradually stabilizes, while the percentage of mixing time gradually increases and the chemical reaction time does not change much. A sufficiently large and reasonable ignition energy power can reduce the ignition delay time and also reduce the impact of the differences between formulations on ignition performance.

Horizontally aligned graphene/silver heterostructure for anisotropically highly thermoconductive polymer-based composites by stress-induced assembly

Urged by the increasing power density of electronics, efficient heat dissipation by graphene-embedded polymer composites with high thermal conductivity (λ) has become a growing demand for addressing overheating issues. However, it is still challenging to achieve a λ over 20 W m−1 K−1 below 20 wt% loading. Herein, we report a highly thermally conductive polymer composite based on self-assembled construction of horizontally aligned graphene/silver (f-GE/Ag) heterostructure, which is fabricated by in-situ deposition of ultra-small Ag nanoparticles on functionalized graphene followed by stress-induced orientation process, consequently achieving efficient heat-transfer pathways with low interfacial thermal barriers. The resultant f-GE/Ag contributes to the composite with a high λ of 25.22 W m−1 K−1 at 15 wt% loading, giving an ultra-high λ enhancement over 12500 %. Additionally, the thermal management application of composites as thermal interface materials integrated with power LEDs is demonstrated. The finding raises the possibility for practical application of high-performance polymer composites in the thermal management of electronics.

Three-dimensional multiphase simulation of a partially narrowed flow field configuration for a high-performance polymer electrolyte membrane fuel cell

A partially narrowed flow field configuration has been recently proposed and applied to the Toyota new Mirai to enhance the mass diffusion and water drainage inside a polymer electrolyte membrane (PEM) fuel cell, thereby elevating the output cell performance. This study performs a 3D multiphase fuel cell simulation to comprehensively investigate the underlying mechanism of mass diffusion and water drainage behavior inside a partially narrowed flow field configuration. Moreover, various structural parameters with respect to the partially narrowed flow field configuration are examined to achieve further enhanced output cell performance. The results indicate that the partially narrowed flow field configuration yields a relatively high pressure drop inside the channel, thereby boosting convective mass diffusion within the electrodes. The total narrowed section length, width and length and arrangement of the individual narrowed section significantly affect the mass diffusion, water drainage behavior, pressure drop and output cell performance. By optimizing the structural parameters of the partially narrowed flow field configuration, substantial improvements in mass diffusion and water drainage inside the fuel cell are achieved. The fuel cell maximum power density increases by 7.5% compared with the traditional straight flow field with a relatively low pressure drop.

Design optimization of proton exchange membrane fuel cell bipolar plate

The bipolar plate geometry design is one of the fuel cell's key features that determines the cell's power. It equally has a direct correlation to the thermal and water management of the cell as it tends to regulate the amount of by-product water that can be expunged from the fuel cell. This study, therefore, explored the development of novel bipolar plate geometry designs, namely the square baffled channel, the rectangular baffled channel, the parallel channel design, and the double serpentine geometry design. This was further compared with the traditional serpentine design to ascertain the design with the optimum fuel cell performance. With the squared baffled channel presenting the best results, varying operating conditions that will influence the performance of the novel fuel cell channel design were also evaluated. It was observed that the hydrogen mass fraction increased by 22.6% for the square baffled channel design compared with the other geometry designs considered in the present study. The square baffle channel showed 12.11% increase in power density and 14.54% increase in current density compared to the rectangular baffle channel. In terms of the parallel channel design, the square baffle showed 18.941% increase in power density and 22.278% increase in current density. The least performing channel geometry design was the double serpentine design. Comparing the double serpentine channel geometry design to the square baffle channel geometry design, there was an increase in current density by 67.72% and 77.88% in terms of power density in favour of the square baffle channel geometry design. The square baffle channel also showed 50% increase in current density and 58.23% increase in power density compared to conventional serpentine channel flow plate geometry design. An adaptive neuro fuzzy inference system (ANFIS) was also adopted to predict the output power of the cell. This was then compared with Feed Forward Back Propagation Neural Network to determine the model with the most accurate results. The adaptive neuro-fuzzy inference model accurately predicted the non-linearities associated with fuel cell performance, hence recommended as ideal for Proton Exchange membrane fuel cell prediction. The main contribution for the study is the development of optimal flow plate geometry design that will ensure maximum fuel cell performance. The current study is aimed at providing technical information to policy makers and the fuel cell industry on how optimization of the flow plate design via the introduction of baffles could increase the cell performance hence accelerates its commercialization and widen their applications in various sectors beyond the automotive industry.

Artificial neural network based modelling and optimization of microalgae microbial fuel cell

Simultaneous wastewater treatment and energy harvesting is attractive topic these days. A microbial fuel cell is an electrochemical device that can be used effectively for this purpose. Microalgae-based MFC is a novel approach to extracting sustainable and economical energy by incorporating photosynthesis with MFC. This paper uses artificial intelligence to identify the best operational factors of microalgae microbial fuel cell (MMFC). The proposed methodology integrates artificial neural network (ANN) modelling and forensic-based investigation algorithm (FBI). Yeast concentration (%) and wastewater concentration (%) are used as decision variables during the optimization process, whereas the objective function is simultaneously maximization of power density and COD removal. Based on the measured data, a ANN model is designed to simulate the power density and COD removal in terms of yeast and wastewater concentrations. Compared with ANOVA, the values of coefficient-of-determination are increased. For the power density model, the coefficient-of-determination in the prediction is increased from 0.7275 to 0.9783 by around 34%. Whereas for the COD removal model, the coefficient-of-determination in the prediction is increased from 0.8512 to 0.9 by around 5.7%. Then, using FBI, the best concentrations of yeast and wastewater are identified to increase power density and COD removal simultaneously. To prove the superiority of the proposed methodology, the optimal parameters and best performance are compared with an optimized performance by response surface methodology and measured data. The performance of MMFC is increased by 2.24%, thanks to the integration between ANN and FBI.

Excellent upconversion luminescence intensity in Er3+/Yb3+/Mo4+ triple-doped BiTa7O19 phosphors

BiTa7O19:Er3+/Yb3+/Mo4+ phosphors with excellent upconversion luminescence (UCL) intensity were synthesized by high temperature solid state method. The crystal structure, grain morphology and valence states of molybdenum ions were determined by X-ray diffraction (XRD), field emission scan electronic microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS) technologies, respectively, and the UCL properties were studied by spectroscopy under 980 nm laser excitation. The green UCL intensity of BiTa7O19:0.1Er3+/0.4Yb3+/0.4Mo4+ is 1.66 times higher than that of commercial NaYF4:Er3+/Yb3+ under 980 nm laser excitation with 18.09 W/cm2. The UCL intensity of BiTa7O19:Er3+/Yb3+ phosphors increased first and then decreased with the increase of 980 nm laser excitation power density (0.38–56.69 W/cm2), while the UCL intensity of BiTa7O19:Er3+/Yb3+/Mo4+ phosphors can keep increasing with the increase of excitation power density. Based upon the luminescence intensity ratio (LIR) technique, the maximum absolute sensitivity (SA) is 0.01046 K−1 at 401 K. The experiment proved that BiTa7O19:Er3+/Yb3+/Mo4+ phosphors had strong acid and alkali resistance compared with NaYF4:Er3+/Yb3+. It indicates that BiTa7O19:Er3+/Yb3+/Mo4+ can replace NaYF4:Er3+/Yb3+ to be applied as luminescence imaging and temperature sensors in complex environments under high 980 nm laser excitation power density.

High power zinc iodine redox flow battery with iron-functionalized carbon electrodes.

The zinc iodine (ZI) redox flow battery (RFB) has emerged as a promising candidate for grid-scale electrical energy storage owing to its high energy density, low cost and environmental friendliness. In this work, ZI RFBs were made with electrodes comprising carbon nanotubes (CNT) with redox-active iron particles, yielding higher discharge voltages, power densities, and 90% lower charge transfer resistances compared to cells with inert carbon electrodes. Analysis of the polarization curves reveals that cells with iron-containing electrodes have lower mass transfer resistances and 100% increase in power density (44 mW cm-2 to 90 mW cm-2) at 110 mA cm-2 relative to cells with inert carbon electrodes.

Reversible charge-polarity control for a photo-triggered anti-ambipolar In2Se3&WSe2 heterotransistor.

Based on the charge-polarity control, a novel anti-ambipolar heterotransistor is proposed based on a special In2Se3&WSe2 van der Waals heterostructure. Unlike traditional logic transistors, our anti-ambipolar heterotransistor can treat an optical signal as an input to change its operating state, that is, with the switching of the optical signal, it shows a reversible polarity change between anti-ambipolar and P-type. Moreover, with the increase of laser power density from 0 to 4.4 mW cm-2, the current value corresponding to the anti-ambipolar peak of the device (Ipeak) shifts from 0 to 4.3 nA, and the voltage value corresponding to the anti-ambipolar peak of the device (Vpeak) can shift from -7 to -5.67 V. These phenomena demonstrate that the charge neutrality point of the anti-ambipolar heterotransistor can be selectively varied with the change of laser power density. In addition, the aforementioned device possesses a high Ion/Ioff ratio of about 104 (405 nm, 4.4 mW cm-2) at 0 V. These properties indicate that our unique anti-ambipolar In2Se3&WSe2 heterotransistor can be employed in photo-triggered inverters for future optoelectronic circuits, and it has great potential to improve the integration of overall chip circuits by implementing optoelectronic logic functions in a unit.

Accurate Determination of Spin-Exchange Relaxation in a Self-Compensated Atomic Comagnetometer

The spin-exchange (SE) relaxation of the electron spins limits the sensitivity of the self-compensated atomic co-magnetometer. In this paper, a novel method for measuring the SE relaxation based on the pulse response of the comagnetometer is proposed. The SE relaxation is measured from the difference between the transverse and longitudinal relaxation of the electron spins, which are synchronously extracted from the responses along the probe and pump laser directions to a series of pulsed magnetic fields. Furthermore, we investigate the variation of the SE relaxation with different pump laser power densities and cell temperatures based on this method. The results indicate that there is a maximum of the SE relaxation with the increase of the pump laser power density, and the pump laser power density corresponding to the maximum increases with the cell temperature. The theory and method presented here not only shed light on the way to suppress the SE relaxation in the self-compensated comagnetometer, but also have the potential to be applied to other optically pumped atomic sensors.

Longitudinal trajectories of spectral power during sleep in middle-aged and older adults.

Age-related changes in sleep appear to contribute to cognitive aging and dementia. However, most of the current understanding of sleep across the lifespan is based on cross-sectional evidence. Using data from the Sleep Heart Health Study, we investigated longitudinal changes in sleep micro-architecture, focusing on whether such age-related changes are experienced uniformly across individuals. Participants were 2,202 adults (ageBaseline=62.40±10.38, 55.36% female, 87.92% White) who completed home polysomnography assessment at two study visits, which were 5.23years apart (range: 4-7years). We analyzed NREM and REM spectral power density for each 0.5Hz frequency bin, including slow oscillation (0.5-1Hz), delta (1-4Hz), theta (4-8Hz), alpha (8-12Hz), sigma (12-15Hz), and beta-1 (15-20Hz) bands. Longitudinal comparisons showed a 5-year decline in NREM delta (p<.001) and NREM sigma power density (p<.001) as well as a 5-year increase in theta power density during NREM (p=.001) and power density for all frequency bands during REM sleep (ps<0.05). In contrast to the notion that sleep declines linearly with advancing age, longitudinal trajectories varied considerably across individuals. Within individuals, the 5-year changes in NREM and REM power density were strongly correlated (slow oscillation: r=0.46; delta: r=0.67; theta r=0.78; alpha r=0.66; sigma: r=0.71; beta-1: r=0.73; ps<0.001). The convergence in the longitudinal trajectories of NREM and REM activity may reflect age-related neural de-differentiation and/or compensation processes. Future research should investigate the neurocognitive implications of longitudinal changes in sleep micro-architecture and test whether interventions for improving key sleep micro-architecture features (such as NREM delta and sigma activity) also benefit cognition over time.

Thermal characteristics of a flat plate pulsating heat pipe module for onsite cooling of high power server CPUs

• An aluminum flat plate pulsating heat pipe radiator was developed for server chip cooling. • The optimal filling rate is about 75-80% with the minimum total thermal resistance of 0.225℃/W. • The cooling module can solve 250W heat load with the chip temperature below 85℃. • The cooling module is more superior in thermal performance to the commercial vapor chamber module. In order to meet the increasing power density and heat dissipation requirements of data center servers, an aluminum-based flat plate pulsating heat pipe module characterized with locally heated on the central region and cooled on the entire rest sides was proposed. Using acetone and R113 as the working fluids, the heat dissipation performance under different liquid filling rates was experimentally studied. Under the condition of the optimal filling rate (75-80%), the heat dissipation capability of 250W can be achieved for acetone with the minimum thermal resistance of 0.225℃/W. Meanwhile, this aluminum-based flat plate pulsating heat pipe module was compared with those of the large FPPHPs and vapor chambers reported in other literatures, especially with the currently available commercial vapor chambers in terms of total thermal resistance and thermal diffusivity, indicating the flat plate pulsating heat pipe module proposed herein is more superior in thermal performance. The flat plate pulsating heat pipe module owns advantages of low cost, light weight and robustness compared to other commercial high power server solutions.

Modified Bi-directional DC-DC converter For EVs

This paper introduces a modified bidirectional DC-DC converter with equal current sharing capacity with 4 times the input voltage. This propose circuit has an excellent conversion ratio for use with electric car applications. The proposed system’s capacitive voltage-divider stage provides minimal stress across the switches, allowing the designer to use small resistance. The alternative arrangement of switches increases power density while significantly reducing current ripple and filter sizing. Two phases are described here, interleaved to construct the equal current sharing phenomena. This connection of converter is thoroughly examined, and its characteristics are studied and compared to those of other state-of-the-art bidirectional converters.